1. Field of the Invention
The present invention relates to a solenoid valve having a movable iron core, which is displaceable under excitation of a solenoid, and in which a communication state of fluid passages are switched by displacement of the movable iron core.
2. Description of the Related Art
Conventionally, solenoid valves have been used, for example, for supplying a pressure fluid to an actuator, or for controlling a flow direction of compressed air by exhausting the pressurized air to the atmosphere. The present inventors have proposed a solenoid valve (see Japanese Laid-Open Patent Publication No. 10-089528), which is capable of causing displacement of a valve body under excitation of a solenoid, for thereby switching a flow state of a fluid.
Such a solenoid valve is constituted by a valve part and a solenoid. The solenoid is equipped with a bobbin around which an excitation coil is wound, a magnetic frame and a mold surrounding the bobbin, a fixed iron core arranged in a central hole of the bobbin, and a movable iron core that slides inside of the central hole of the bobbin, with a valve plug being disposed on an end of the movable iron core. Further, plural guide rings are disposed on an outer circumferential surface of the movable iron core, the movable iron core being guided in the axial direction by the guide rings. In addition, a cushion member is disposed on the movable iron core for regulating displacement of the movable iron core.